Fix bug in verify script preventing the use of '.' in marketplace-reserved keys (#434)
Fix bug in verify script preventing the use of '.' in marketplace-reserved keys (#434)

By running `jq ".$key = value`, any value of `$key` with a period would create a parameters payload with nested values. However, later scripts (e.g. deployment) assume that parameters is a flat payload.

For example, my reporting secret is stored in a key named "ubbagent.reportingSecret". During verify, this parameter is inferred by `extract_schema_key.py`. After a fake secret is created, the key is added to the parameters payload using `"echo $parameters | jq ".ubbagent.reportingSecret" = "some-key-name"`. The resulting payload is:

```json
{
  "name": "...",
  "namespace": "...",
  "ubbagent": {
    "reportingSecret": "some-key-name",
  }
}
```

This is wrong, and causes later steps to fail with "no property defined in schema: ubbagent". Instead, the parameters struct should be:

```json
{
  "name": "...",
  "namespace": "...",
  "ubbagent.reportingSecret": "some-key-name",
}
```

By quoting the key names in the jq command, this above payload is generated instead, fixing the issue.
GoogleCloudPlatform/marketplace-k8s-app-tools,GoogleCloudPlatform/marketplace-k8s-app-tools